From: Guus Sliepen <guus@meshlink.io>
Date: Tue, 29 Sep 2020 20:38:55 +0000 (+0200)
Subject: Send RST packets when receiving data after we closed a UDP channel.
X-Git-Url: https://git.meshlink.io/?a=commitdiff_plain;h=1a023116b9d5e9a8fa93e81fcef725fd7b343593;p=meshlink

Send RST packets when receiving data after we closed a UDP channel.

If the application closed a channel, we keep the UTCP connection alive for
a bit longer to handle resends of FIN packets. However, if this is missed
for some reason, either because the FIN got lost or the peer ignored the
receive callback, and the peer is sending new data, we need to inform it
that we are no longer listening. To do this, send a RST back.
---

diff --git a/src/utcp.c b/src/utcp.c
index 65e6be7a..c1add218 100644
--- a/src/utcp.c
+++ b/src/utcp.c
@@ -1559,6 +1559,11 @@ synack:
 	advanced = seqdiff(hdr.ack, c->snd.una);
 
 	if(advanced) {
+		if(c->reapable && !is_reliable(c)) {
+			// TODO: we should also send RST for reliable connections
+			goto reset;
+		}
+
 		// RTT measurement
 		if(c->rtt_start.tv_sec) {
 			if(c->rtt_seq == hdr.ack) {